WASHINGTON - Recent attacks in the United States, including in a Walmart store on El Paso, Texas and a synagogue in Pittsburgh, Pennsylvania have raised concerns over the growing threat from domestic extremist groups.

U.S. law enforcement officials and experts now are discussing ways to help counter such groups, using similar to steps the U.S. government took when it expanded its fight against foreign terrorist organizations following the September 11, 2001 attacks.

WATCH: Strategies to counter domestic attacks

Countering the Rise of Domestic Extremism in the US video player. Embed Copy

It was during last month's mass shooting in El Paso that the term domestic terrorism created some confusion.

That's because the attack, which killed 22 people, was treated by federal law enforcement officials as a case of domestic terrorism.

The attacker, however, was not charged with terrorism, but with capital murder.

The reason, according to experts, is that the United States doesn't have a federal statute that penalizes American citizens who are regarded as domestic terrorists. Those regarded as domestic terrorists are charged under laws related to hate crimes, guns and conspiracy.

Domestic vs international

According to federal law, in order to be charged with terrorism, a person must be suspected of acting on behalf of a group that is designated by the U.S. government as a foreign terrorist organization.

"The government thinks of something as international terrorism even if it occurs here domestically in the U.S., if it is done in furtherance of the goals of foreign terrorist organizations like ISIS and al-Qaida," said Mary McCord, a former Acting Assistant Attorney General for National Security, using an acronym for the Islamic Stater (IS) terror group.

"The government considers it domestic terrorism if it occurs here in the U.S., but it's based on other ideologies. It's based on just an intent to intimidate or coerce or to influence the policy of government through intimidation or coercion not related to a foreign terrorist organization," she said Monday during remarks at the Center for Strategic and International Studies (CSIS) in Washington.

US Congress

Experts said some U.S. lawmakers have been exploring the idea of what value a domestic terrorism statute could bring to help law enforcement agencies counter the rise of domestic terrorists more effectively.

Nicholas Rasmussen, Director for National Security and Counterterrorism Programs at McCain Institute, says that any legislation introduced on this issue "would generate a healthy debate as it should."

"There is some effort under way to try to determine what actually would that do in the way of giving law enforcement more tools than they currently have and how you balance that against any concerns that might exist about the way that might constrain free speech or be viewed as a tool that could somehow be used against other forms of political expression over time," he said at the CSIS event.

According to the Center for the Study of Hate and Extremism at California State University, killings committed by white supremacists have surpassed those of Islamist extremists in the U.S. in recent years. Since 2018, they have killed 42 people, while jihadists affiliated with foreign terrorist groups committed one homicide over the same period.

Partnership

While social media companies have been trying to limit the presence of domestic extremists, experts said that curbing their online activities requires a real partnership between public and private sectors.

"The solution set here cannot be, government needs to do this and the private sector, technology companies, and social media need to do that," George Selim, Senior Vice President of Programs at the Anti-Defamation League.

"The solution set moving forward is partnership in a very integrated model where government and law enforcement at the state and local levels, and also local community-based actors [such as] mental health, social service and education providers. We need to apply a comprehensive set of solutions to this issue set today," Selim, a former Director of the Office for Community Partnerships at the U.S. Department of Homeland Security, added.

Experts also noted that domestic extremism in all its forms is a global problem, and therefore governments around the world need to confront it together.